crucible  
noun [ C ] uk/ˈkruː.sɪ.bəl/ us/ˈkruː.sə.bəl/
  (CONTAINER)     
  坩埚
a container in which metals or other substances can be heated to very high temperatures
   (TEST)     
  formal严峻的考验;磨炼 
a severe test
   (MIX)     
 formal(融合不同文化或风格而产生新生事物的)熔炉 
a place or situation in which different cultures or styles can mix together to produce something new and exciting